Nikon 17-55 for "Macro"???

So thinking about selling my 17-35mm, which is my favorite all around lens. How good will the Nikon 17-55 be for “macro†type shots behind a 8†dome port? (Aquatica)

Few seem to be using the 17-55. I got one with my D70 instead of the 18-70 kit lens. Its taken awhile to get it set up on my Nexus, doing a series of pool tests with different domes. I settled on a 190mm (about 7.5") diameter port, with a +4 diopter on the lens. Looks good in the tank. Very good image quality & sharp edges. Haven't dove it yet thou. I got this lens to use as a general purpose lens - diving a site where I don't know what to expect. I don't plan on using it as a macro lens. It will focus at about 12" (from the sensor plane) with the diopter. So sorta close but no true macro capability. A quick check gives a magnification ratio of 3.2. The nodal point (entrance pupil) for the lens at 17mm is about 125mm from the sensor plane. That's where the center of curvature of the dome should be (+/-). I also found that what may look like a hemispherical (180 deg) dome is not always the case. Measure to be sure. The 8" dome will work better than a 6". The standard Nexus dome is 170mm - not nearly as good for this lens.

I have used this lens with my Subal. It does not focus close enough for macro. It's been awhile but I think the best you can do is around 1:5 to 1:4 mag. It also doesn't get wide enough for really good wide angle. It is however a fine lens for fish shots. I primarily bring it as a backup in case a problem with one of my other lenses.

I sold my 17-35 to buy the lens and have never regretted the decision.

The 8" dome will work better than a 6". The standard Nexus dome is 170mm - not nearly as good for this lens.

These are the measurements of the diameter of the dome ports, and tell you nothing about the optical qualities of the port.

The Athena 170mm Glass Dome Port actually has a larger radius of curvature (better optics) than the Aquatica dome, but is smaller. You are correct that the Nexus FP170 acrylic port is inferior.

I only know of 2 hemispherical domes being sold, so that is far from the norm.

Thanks for the help. I did not think you could shoot "true" macro but it would be nice to be able to shoot divers down to say ghost pipe fish with one lens. As others have noted this would be a lens I lean to when I don't know what to expect or say larger creatures that might be to shy for the 12-24. Thinking Cocos hamerheads.

Ryan - Thanks for the clarification. I was not implying that one should shop for a true hemisphere - only referring to the dome geometry. In determining where the center of curvature of the dome is located, you can be off on the measurement if what looks to be a hemi is actually not. Looking at my 170 dome it looked like a hemi, but when I measured to the base ring it was 20mm short. That added 20mm is the extension ring I chose to use.

Thanks for the help.  I did not think you could shoot "true" macro but it would be nice to be able to shoot divers down to say ghost pipe fish with one lens.  As others have noted this would be a lens I lean to when I don't know what to expect or say larger creatures that might be to shy for the 12-24.  Thinking Cocos hamerheads.

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You can certainly do that, and I think this would be a great shark lens. Check this topic for some samples:

http://wetpixel.com/forums/index.php?showtopic=12200

Luiz

Ryan:

What is the inside radius of the Athena 170mm glass port- and why does it have better optics than the Aquatica dome port?

On another note, the 17-55 has never been a macro lens.

Mauricio Handler

Athena will not publish the numbers, neither does Aquatica to my knowledge. I determined that the dome has a larger radius of curvature by holding them side by side. It is generally accepted that a larger radius of curvature is optically better. Further, the dome is coated glass, which is more transmissive of light than uncoated acrylic.

The Athena dome is also nearly twice the price, to be fair, and plenty of good photographers have "made do" with the Aquatica port, right Mauricio?

You can determine the radius of a dome as follows (assuming dome is resting on a flat horizontal surface):

(sorry I can't write proper equations here)

r = (x**2 + y**2)/2y

read as x squared

x = horizontal distance measured from vertical centerline to where dome intersects base plate

y = veritcal distance measured from upper most point of dome on vertical centerline to where dome intersects base plate

Hope this is clear. Had to calculate the Nexus domes also.

It may be a little difficult to measure some domes. Just do the best you can. You will be within a few millimeters.

I use the 17-55 with my Aquatica housing, the gearing is custom made, Blake at aquatica knows what to do. The extention is the 105mm and it all works great, no diopters, corners are fine. Forget macro, but still a super sharp and versitile lens

Ryan,

If Athena does not publish the numbers,maybe you could just measure it with a ruler or caliper,and here is the formula to convert mm to inches, it is .03937.So maybe there 170 dome is 6.6929 inches?The Aquatica dome 7.500 inside diameter and has a wall thickness of .250,this wall thickness is needed for the depth pressure that the Aquatica housings can go.As for the transmissive of light on the glass domes being better,I am not sure about this. Do you have any side by side images that show this difference? There are alots of working pros out there that are using the Aquatica dome,and alot that used it in the 35mm days, and remember 35mm is full frame,therefore optics and nodal points are very critical. David Doubilet used the Aquatica F4 AND f5 on many of his shoots and I think he has taken a few good images in his time,he is the master of lighting. He does use some Nexus housings these days,but when you see him with a larger dome on these housings,it is the Aquatica dome with a custom adaptor. Aquatica sells there domes to the National Geographic for conversion. I can also make a long list of pros that have relied heavily on the Aquatica domes over the past 20 years.

I have no doubt that glass is good, but I have no reason to think that the Aquatica is not as good. Advantages of Aquatica ports include the ability to be able to repair scratches in the field. They are also lighter and cost 1/3 of glass ports. In addition, you only require one Aquatica 8" dome port to do the job of multiple smaller glass ports. We use one port for all lenses from the 10.5 - short barrel zooms. The key is in using the correct extension ring on the dome to accommodate some of these lenses.

So to wrap this up, I am confident that both glass and Aquatica ports can pull of the most demanding jobs in the field. If one is better than the other is really a matter of preference and budget.

Mauricio Handler

Guys,

There are many other thread discussing the difference between glass and acrylic domes. No need to rehash it again. But I'll summarize here:

Coated optical glass has better light transmission and anti-reflective properties, but it costs more.

Glass is harder to scratch, but if it does scratch you can't repair it. Acrylic is easy to scratch but easy to repair.

With all that said, I used the Aquatica 8" dome w/ the FF 5D last week with excellent results.

Cheers

James